Laser distance measuring can be employed in robotic welding operations. Employing a laser permits accurate determination of the location of a weld seam between two surfaces. In operation, a laser light is emitted and impinges upon one surface, then the other surface, to find the exact intersecting weld seam.
In the past, this location was performed by using the wire stick out from the welding torch, to touch sense each surface, in finding the weld seam. For touch sensing with coordinated motion, the touch frame relative to the UFRAME of the robot (follower) was selected of the coordinated frame of the reference group (leader). The reference group was set for the leader group so that the search direction will be relative to that group.
Typically, only one search motion is used for each search direction. Some search patterns require two search motions in each of two search directions for the software to calculate an angular offset. Search patterns determine the type of information stored in the position register. The stored information is either the found position or position offset information depending on the search pattern used.
Up to five search motions in one search direction can be done to improve the accuracy of locating an object. When more than one search motion in a direction is used, the software calculates an average value of the searches and uses the average for the offset calculation except when using the search pattern 1D+Rotate, 2D+Rotate, or 3D+Rotate.
The laser is much more accurate and preferred by many customers. However, in light of the fact that the laser is positioned in close proximity to the welding gun, the lens of the laser often becomes contaminated with welding fumes and spatter, resulting in inaccurate measurements.
What is needed is a laser enclosure which houses the laser generating apparatus, and which is under positive internal pressure and/or positive gaseous flow about the laser lens, so as to protect the lens from contamination by the welding operation.